The present invention relates to the art of electroplating and particularly to the art of electroplating small articles, for example portions of small metallic parts where the electroplated portions are used in the electronics industry as contact surfaces and relates more particularly to the art of goldplating electronic components. In some instances it is desirable to plate inside portions of tubular articles as well as outer surfaces.
The growth and increased sophistication of the electronics industry has led to the need for electroplated components and particularly for electroplated contact areas of various description where the contact areas are usually electroplated with gold to prevent corrosion and erosion of contact areas and maintain reliable electrical conductivity of the components.
Gold has become recognized as the leading plating material because of its relative unalterability, good solderability and low contrast resistance.
Some prior art arrangements are known for plating of such contacts has been accomplished by so called "barrel plating" techniques where the articles are tumbled in a barrel as the plating is applied.
Such techniques are expensive because of the increased price of gold coupled with the use of excess material in such procedures because such techniques are not specific as to areas to be electroplated and lead to plating unnecessary areas and overplating. Accordingly, the use of techniques to plate only contact surfaces as provided by the present invention have come to be appreciated.
One prior art arrangement for selective plating is shown in U.S. Pat. No. 3,904,489 which utilizes a porous felt type applicator which is used to apply the electroplating solution to the parts which are carried by a continuous belt by insertion therethrough.
Another prior art arrangement which is an improvement in the aforenoted arrangement is shown in U.S. Pat. No. 3,966,581.
Another arrangement is shown in my co-pending application Ser. No. 323,441, filed Nov. 20, 1981.
Electroplating processes are also utilized for electroplating contact areas of printed circuit boards as shown in U.S. Pat. No. 4,155,815-Francis, et al. where endless tractor belts are utilized to hold printed circuit boards for selective electroplating.
No prior art devices are known to accomplish continuous electroplating of selected articles where the articles are sequentially carried in selected orientation through electroplating bath by means of apertures in a moving conveyor to electroplate only selected portions thereof while electrical contact is maintained between internal from a contact strip in contact with a first portion of the article while the downwardly depending portion of the article to be electroplated is immersed in the electroplating solution.